With the increase of the applications of slow neutron detection and imaging technology in such aspects as homeland security, material monitoring, slow neutron scattering source measurement, the demands on the slow neutron detector are gradually increasing. However, the widely applied 3He gas no longer satisfies the constantly increasing use demands, and thus different types of new slow neutron detectors are developed to replace the 3He gas detector, including the gas slow neutron detector, the scintillator slow neutron detector, the semiconductor slow neutron detector and the like.
With respect to a slow neutron detector, a slow neutron converter is an important structure therein. Since the slow neutrons themselves carry no charges, except for a few types of slow neutron sensitive nuclide such as 6Li, 10B, Gd and the like, the slow neutrons have a small reaction cross-section with other substances, which causes that the slow neutrons are hard to be directly detected. Inside of the slow neutron converter is rich in a large quantity of slow neutron sensitive nuclide, which can convert the slow neutrons into charged particles through nuclear reactions. The detector may conveniently measure the energy and position information of these charged particles, which obtain relative physical information of the incident slow neutrons.
In design of the gas slow neutron detector, depending on the used basic detector, there may be a plurality of types of slow neutron converters and slow neutron detectors. Such as the gas slow neutron detector based on a cylindrical proportional detector array, and the gas slow neutron detector based on a multiple plate ionization chamber.
In the gas slow neutron detector based on a cylindrical proportional detector array, a most basic slow neutron detection unit is a cylindrical proportional detector, and each unit has an independent anode wire and a signal collection and processing system. A typical example is the “straw tube” slow neutron detector array. However, the slow neutron sensitive area and the slow neutron detection efficiency of the detector are substantially proportional to the square of the quantity of cylindrical proportional detectors. In the system, installation and repair of a large quantity of anode wires would cause a great workload, and the difference in the detection efficiency among various slow neutron detection units would also affect the performance of the entire system.
In the gas slow neutron detector based on a multiple plate ionization chamber, the most basic slow neutron detection unit is a plate ionization chamber, and each ionization chamber has an independent two-dimensional signal readout system. A typical example is the B-GEM slow neutron detector. However, a single-layer plate ionization chamber has a low slow neutron detection efficiency, and thus some methods are needed to be employed to improve the overall slow neutron detection efficiency, such as the multiple chamber stacking, slow neutron incidence with a grazing angle. However, this would cause a great pressure on the overall signal readout and processing, and thus large-area slow neutron detection is inconvenient to be implemented.
Therefore, a new slow neutron converter and a new slow neutron detector are desired.
The above information disclosed in the background portion is only used to reinforce understanding of the background of the present disclosure. Therefore, the above information may include information that is not prior arts known to persons of ordinary skill in the art.